Originally built as Geoyeolseong (Geoyeol Castle) during the Three Kingdoms Period, it was later renamed Chokseokseong in the Goryeo Dynasty and finally Jinjuseong during the Joseon Dynasty. Although it's called a "castle," it mainly served as a fortress, defending the Honam region from Japanese invaders during the Imjin Waeran. One of the best renovated fortresses in the country, Jinjuseong sits on the north side of the Nam-gahng overlooking the city. Inside the east gate is the famous Chokseong-nu pavilion. Other outlooks and pavilions are along the fortress wall, with the highest one at the southwest corner. Also inside the walls are a memorial to Kim Shi-min, the Uigisa Shrine, Seojangdae, Bukjangdae, the Changyeolsa shrine, the temple Hoguksa, and an outdoor stage. The complex is spectacular at night when its lights are reflected in the river below.
The Jinju National Museum (tel. 055/742-5951; http://jinju.museum.go.kr) offers an in-depth history of the Imjin Waeran. Hours are Tuesday to Friday 9am to 6pm, until 7pm on weekends; the museum closes at 5pm November to February. It's closed January 1. Admission is an additional W1,000 adults, W500 ages 7 to 18, free for adults 65 and over and children 6 and under.